Dilation is a technique for creating similar figures.
Each point is stretched outwards from the center point D by multiplying distances by the scale factor. (Outwards if the scale factor is bigger than 1.)
Move the points A, B, C to change the shape of the triangle.
Move the center point D to dilate from a different location.
Use the slider to change the scale factor.
Distances and ratios are measured and computed in the spreadsheet window. (Spreadsheet window does not appear if you are viewing this on a phone.)

What happens when the scale factor is bigger than 1?
What happens when the scale factor is equal to 1?
What happens when the scale factor is between 0 and 1?
What happens when the scale factor is equal to 0?
What happens when the scale factor is negative?
What happens when the center point (D) is inside the triangle?
What happens when the center point (D) is outside the triangle?
What happens when the center point (D) is at a vertex of the triangle?